[systemd-devel] WebUSB

Greg KH greg at kroah.com
Tue Jan 10 17:33:12 UTC 2017


On Tue, Jan 10, 2017 at 06:23:13PM +0100, Lars Knudsen wrote:
> 
> 
> On Jan 10, 2017 18:19, "Greg KH" <greg at kroah.com> wrote:
> 
>     On Tue, Jan 10, 2017 at 06:04:46PM +0100, Lars Knudsen wrote:
>     > I figured that made most sense :)
>     >
>     > Still, it would be good if we could have a rule to not grab the CDC
>     interface
>     > part if the device includes WebUSB functionality.
> 
>     What exactly do you mean by "grab"?
> 
> MM probing :)

Probe should be fine, right?  Are you really thinking that MM needs to
go "oh look, a cdc device, let's go look at all of the raw interfaces to
ensure it really isn't a webusb device as well before I touch it!"

That way lies madness...

What's wrong with touching it?  The kernel already did, why would
userspace care?

>     > The likelihood of a modem+WebUSB combo is so small that it must fall
>     > in the category where potential rare exotic devices combining it must
>     > be whitelisted and the rest be left alone.
> 
>     I think you misunderstand just how crazy firmware authors can be.  I'm
>     sure we will see those types of devices in the wild.
> 
> ...But realistically how many? Bothering 99.9% to support the special case
> seems less logical than just finding the 0.1% and whitelisting it (if needed)

That's the joy of writing an operating system for all devices on the
planet, those 0.1% can be a lot of devices :)

Anyway, I don't think there's much to do here just yet, let's wait and
see just how bad these webusb devices end up looking like...

thanks,

greg k-h


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